Nanolithography and Manipulation Combined with AFM

Nanolithography and manipulation capabilities have actually been around for quite some time. Remember the 1990 famous IBM image of Xenon atoms manipulated using STM? Today’s demanding applications require incredibly precise and flexible instrumentation. The MicroAngelo feature within the MFP-3D System offers the most comprehensive capabilities of any AFM for nanolithography and manipulation applications.

Built-in Capabilities Without Added Expense

With MicroAngelo, you can manipulate and modify samples and surfaces on the nanometer and picoNewton scale-even down to the level of single molecules. Because the accuracy and precision of MicroAngelo originates with the MFP-3D’s controller, scanner and software, MicroAngelo comes standard with every MFP-3D- there is no need for any extra hardware or software.

NPS™ Closed Loop for Unparalleled Repeatability

At the heart of MicroAngelo’s precise operation is the patent pending Nanopositioning System (NPS) sensor in the MFP-3D. The NPS’ sensored, closed loop operation in all three axes provide sub-nanometer resolution over the entire 90μm scan range, with sensor noise <0.6nm absolute deviation in a 0.1-1kHz bandwidth for X and Y, and <0.3nm in Z. This allows repeatable imaging, quantitative feature measurement, reliable and accurate imaging offsets, quantitative force curves, and quantitative positioning for manipulation and lithography.

Fully-Digital, Low Noise Controller

The MFP-3D controller provides users with the most modern architecture available today. The all-digital system means that the signal is not corrupted by analog signal conditioning that is typical in other commercial units. New functionality can be added quickly and easily with software and firmware upgrades. MicroAngelo is a case history that represents the ease and power with which new functionality can easily be created.

Incredibly Powerful IGOR Pro Software

The flexible, powerful, and open software is based in IGOR Pro and allows the user virtually unlimited ability to modify routines and do “special” experiments. Other powerful routines include nonlinear curve fitting to arbitrary user-defined functions, 2D FFT’s, wavelet transformations, convolutions, line profiles, particle analysis, edge detection (eight methods, including Sobel), and thresholding (five methods, including fuzzy entropy) and more. Unlike proprietary software, if you don’t find a feature you want, you can simply write your own.

Applications

MicroAngelo can be used for many nanolithography and manipulation applications including surface scratching and patterning, localized surface oxidation, nanotube and particle manipulation, molecular manipulation, single molecule experiments and more.

MicroAngelo Examples

With MicroAngelo, users can easily import curves from a variety of other programs or generate them within the MFP-3D software environment as shown in Figure 1. An original JPEG image was imported into the software and converted to a list of coordinates which created the lithography pattern. These coordinates were then used to manipulate the AFM tip which created the scanned image.

Figure 1. Coordinates of the imported JPEG line drawing (left) and AFM phase image (right) of nanolithographically etched polycarbonate, 5μm scan. The original JPEG scan is a copy of Pablo Picasso’s, “Don Quixote”.

Figure 2 shows a pre-programmed array of pits created at different loads. In addition to providing identation information, this is a useful test for calibrating a cantilever and tip for performing “scratch” lithography (see Figure 1).

Figure 2. Arrays of pits created at different loading forces, 5μm scan.

Figure 3 shows before and after scans on Lambda digest DNA in fluid. Force curves were made at user-selected sites 1, 2 and 3 (“before” image). The DNA appears wider on the “after” images because the tip has picked up contaminants (presumably DNA) while performing the force curves. The force curves show the characteristic B-S transition of stretched DNA.2 The length scales of the B-S plateau correspond to the DNA pulled off the surface (compare the before and after images).

Figure 3. Lambda digest DNA,1μm scan, with force curves taken at three different, mouse-selected points (right). Different portions of the B-S transition are visible in the force curves.

Figure 4 shows cutting bacterial flagellum. The initial image (top) was made with a Bio-Lever in AC/repulsive mode in fluid. The left images (A, C) indicate areas designated for cutting (yellow lines). Images B and D show the result of the respective cut. In all of the images of this sample, the color scale was 10nm and the scan size was 5μm.

Figure 5 shows cutting and pushing nanowires. The initial image (top) was made in AC/repulsive mode in fluid. The yellow lines in left images A and C indicate the path of the cantilever tip. Images B and D show the results of the manipulation. In all of the images of this sample, the color scale was 15nm and the scan size was 7.4μm.

Figure 5. Cutting and pushing nanowires, 7.4μm scan.

Figure 6 shows a bundle of SWCNTs rolling left (Figures A, B and E, F,) and right (Figures C, D and G, H). The initial image shows a single isolated bundle. This image was made in AC/repulsive mode with an amplitude of roughly 100nm. A larger bundle is visible on the right side of the smaller bundle. An atomic step is also visible in the image. Images A, C, E and G show the yellow sketched cantilever tip paths made using the MicroAngelo interface. Figures B, D, F and H show the effects of the manipulation areas.

During the manipulation, the normal loading force was set to 90nN. The nominal velocity of the cantilever tip was 1μm/second. In all of the images, the color scale was15nm and the scan size was 1.45μm.

Power and Flexibility in One Complete System

You’ll find all the power and flexibility of MicroAngelo built into each MFP-3D System. Contact us today or send us your samples to see why the MFP-3D is the AFM of choice for nanolithography and manipulation.

All data types are available for plotting during lithography including deflection, lateral force, amplitude, phase and all of the user analog to digital converters (ADCs) and digital to analog converters (DACs).

No latentcy between points 65ms or greater compared to other systems which may stream points out sequentially with latencies greater than 65ms.

Groups of points are sent to the controller and processed at the natural controller interrupt rate. Complex patterns that are typical in anodic oxidation applications are easily drawn.

Lithography can be operated in either vector based or bitmapped modes.

Lithographic contrast can be controlled by modulating the cantilever set-point (either contact or AC modes available), the cantilever drive voltage, cantilever potential or any other channel including the user DACs.

The software is compatible with a variety of input devices including popular graphics tablets such as Wacom Graphire and Intuos.

This information has been sourced, reviewed and adapted from materials provided by Asylum Research - An Oxford Instruments Company.

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Asylum Research - An Oxford Instruments Company. (2019, September 09). Nanolithography and Manipulation Combined with AFM. AZoM. Retrieved on September 15, 2019 from https://www.azom.com/article.aspx?ArticleID=3511.